Abstract: A wireless communication apparatus receives an quadrature modulated signal, generate a local signal having a frequency different from a center frequency of the quadrature modulated signal, performs quadrature demodulation on the quadrature modulated signal by using the local signal, to obtain an I channel signal and a Q channel signal, performs Fourier transform on the I channel signal and the Q channel signal, to obtain signals in a frequency domain, and calculates a first correction coefficient for correcting phase distortion and amplitude distortion caused by the quadrature demodulation by using pairs of signals among the signals, each of the pairs are located at symmetrical frequency positions with respect to the frequency of the local signal.

Abstract: A receiver of an OFDM signal includes a reception unit to receive an OFDM signal formed by a plurality of OFDM symbols respectively including data subcarriers to which data signals are allocated and pilot subcarriers to which cyclically shifted pilot signals are allocated in frequency domain, an estimator to estimate phase errors of the pilot signals to generate first estimated values related to an offset of the OFDM symbol corresponding to each two or more OFDM symbols in the OFDM signal, a weighting adder to perform weighting additions on the first estimated values to obtain one second estimated value related to the offset, a compensator to compensate the offset by using the second estimated value to obtain a compensated OFDM signal, and a decoder to decode the compensated OFDM signal to reproduce the data signals.

Abstract: A wireless communication apparatus includes a plurality of antennas, transmits a plurality of known symbol sequences each including a plurality of known symbols by using the antennas, each of the known symbols having subcarrier arrangement on which plural known information of the each of the known symbols are carried on, and inversion/non-inversion of a phase of known information on one of two adjacent subcarriers of the subcarrier arrangement being controlled in accordance with the number of the known symbols and time position of the each of the known symbols, and transmits data symbols by using the antennas after the known symbol sequences are transmitted.

Abstract: A wireless device, method, and signal for use in communication of a wireless packet between transmitting device and a wireless receiving device via a plurality of antennas, wherein a signal generator generates wireless packet including a short-preamble sequence used for a first automatic gain control (AGC), a first long-preamble sequence, a signal field used for conveying a length of the wireless packet, an AGC preamble sequence used for a second AGC to be performed after the first AGC, a second long-preamble sequence, and a data field conveying data. The AGC preamble sequence is transmitted in parallel by the plurality of antennas.

Abstract: A wireless device, method, and signal for use in communication of a wireless packet between transmitting device and a wireless receiving device via a plurality of antennas, wherein a signal generator generates wireless packet including a short-preamble sequence used for a first automatic gain control (AGC), a first long-preamble sequence, a signal field used for conveying a length of the wireless packet, an AGC preamble sequence used for a second AGC to be performed after the first AGC, a second long-preamble sequence, and a data field conveying data. The AGC preamble sequence is transmitted in parallel by the plurality of antennas.

Abstract: A wireless device, method, and signal for use in communication of a wireless packet between transmitting device and a wireless receiving device via a plurality of antennas, wherein a signal generator generates wireless packet including a short-preamble sequence used for a first automatic gain control (AGC), a first long-preamble sequence, a signal field used for conveying a length of the wireless packet, an AGC preamble sequence used for a second AGC to be performed after the first AGC, a second long-preamble sequence, and a data field conveying data. The AGC preamble sequence is transmitted in parallel by the plurality of antennas.

Abstract: A receiving method receiving an OFDM signal including a first OFDM symbol having first and second pilot signals allocated to first and second subcarriers positioned symmetric on the frequency axis, and a second OFDM symbol having third and fourth pilot signals allocated to the first and the second subcarriers, a difference between a product of the first pilot signal and a complex conjugate of the fourth pilot signal and a product of the third pilot signal and a complex conjugate of the second pilot signal being non-zero, estimating a first coefficient representing a change components of an amplitude and a phase, and a second coefficient representing an interference component, using first and second received pilot signals corresponding to the first and third pilot signals, estimating from the first and second coefficients IQ imbalance, and compensating the influence of amplitude and phase errors in accordance with the IQ imbalance.

Abstract: A transmitting method of OFDM signal includes allocating first and second channel estimation preamble signals for channel response estimation respectively to +kth and ?kth subcarriers from center frequency of first OFDM signal, allocating first and second pilot signals for residual phase offset estimation respectively to +kth and ?kth subcarriers from center frequency of second OFDM signal, transmitting first and second OFDM signals respectively in different time zones using at least one antenna, where, first product of complex conjugate of first channel estimation preamble signal and second pilot signal is equal to second product of second channel estimation preamble signal and complex conjugate of first pilot signal.

Abstract: A wireless device, method, and signal for use in communication of a wireless packet between transmitting device and a wireless receiving device via a plurality of antennas, wherein a signal generator generates wireless packet including a short-preamble sequence used for a first automatic gain control (AGC), a first long-preamble sequence, a signal field used for conveying a length of the wireless packet, an AGC preamble sequence used for a second AGC to be performed after the first AGC, a second long-preamble sequence, and a data field conveying data. The AGC preamble sequence is transmitted in parallel by the plurality of antennas.

Abstract: A wireless communication apparatus includes a first storage unit configured to store each of a plurality of upper limit values of absolute values of additional signals that are set for a corresponding one of a plurality of first wireless communication apparatuses and are added when a plurality of modulation symbols to be transmitted to the first wireless communication apparatuses are precoded, a coding unit configured to decide each of a plurality of first values of the additional signals for a corresponding one of the first wireless communication apparatuses within ranges defined by the upper limit values, and precode the modulation symbols using the first values to obtain a plurality of transmission signals, and a first transmission unit configured to transmit, using multi-user MIMO (Multiple Input Multiple Output), the transmission signals to the first wireless communication apparatuses.

Abstract: A wireless communication method includes generating and transmitting an OFDM signal containing a first OFDM symbol possessing a first transmitting pilot signal and a second transmitting pilot signal respectively allocated to a first subcarrier and a second subcarrier being symmetric with respect to a center frequency on a frequency axis, and a second OFDM symbol possessing a third transmitting pilot signal and a fourth transmitting pilot signal respectively allocated to the first subcarrier and the second subcarrier, wherein a difference between a product of a first transmitting pilot signal and a complex conjugate of a fourth transmitting pilot signal and a product of a third transmitting pilot signal and a complex conjugate of a second transmitting pilot signal is non-zero.

Abstract: A wireless device, method, and signal for use in communication of a wireless packet between transmitting device and a wireless receiving device via a plurality of antennas, wherein a signal generator generates wireless packet including a short-preamble sequence used for a first automatic gain control (AGC), a first long-preamble sequence, a signal field used for conveying a length of the wireless packet, an AGC preamble sequence used for a second AGC to be performed after the first AGC, a second long-preamble sequence, and a data field conveying data. The AGC preamble sequence is transmitted in parallel by the plurality of antennas.

Abstract: A wireless device, method, and signal for use in communication of a wireless packet between transmitting device and a wireless receiving device via a plurality of antennas, wherein a signal generator generates wireless packet including a short-preamble sequence used for a first automatic gain control (AGC), a first long-preamble sequence, a signal field used for conveying a length of the wireless packet, an AGC preamble sequence used for a second AGC to be performed after the first AGC, a second long-preamble sequence, and a data field conveying data. The AGC preamble sequence is transmitted in parallel by the plurality of antennas.

Abstract: A wireless device, method, and signal for use in communication of a wireless packet between transmitting device and a wireless receiving device via a plurality of antennas, wherein a signal generator generates wireless packet including a short-preamble sequence used for a first automatic gain control (AGC), a first long-preamble sequence, a signal field used for conveying a length of the wireless packet, an AGC preamble sequence used for a second AGC to be performed after the first AGC, a second long-preamble sequence, and a data field conveying data. The AGC preamble sequence is transmitted in parallel by the plurality of antennas.

Abstract: Radio communication apparatus includes unit dividing transmit data into first-and-second streams, unit subjecting first-and-second streams to serial-to-parallel conversion to obtain data signals, unit modulating data signals into OFDM-modulation signals corresponding to first and second streams using subcarriers, unit acquiring channel responses between communication and receiving apparatuses, unit computing singular values ?1(k) and ?2(k) of channel matrix corresponding to kth subcarrier in subcarriers, based on channel responses, unit assigning weights corresponding to singular values ?1(k) and ?2(k) to first-and-second streams where correspondence of weights to streams is different by subcarrier, unit multiplying, by each of assigned weights, OFDM-modulation signals corresponding to each of first and second streams, and acquire first-and-second signals corresponding to first-and-second streams, unit adding first-and-second signals to acquire added signals, unit subjecting added signals to inverse-Fourier t

Abstract: A radio communication apparatus includes: generation units generating first to mth signals; a storage storing allocation information defining that beams of different quality levels are allocated to first to mth communication apparatuses for each of first to nth subcarriers so that frequencies of respective quality levels are substantially uniform over all the subcarriers among the apparatuses; determining units determining transmission weights by which the signals are multiplied so that the beams according to the allocation information are formed for the apparatuses for each of the subcarriers; generation units performing multiplication processing by using the signals and the weights for each of the subcarriers to generate first to hth weighted signals for each of the subcarriers; transform units performing inverse Fourier transform on the weighted signals for each of the subcarriers to generate first to hth transformed signals; and transmission processing units transmitting the transformed signals via first

Abstract: A terminal apparatus includes: a reception unit configured to receive a signal from a base station; a channel estimation unit configured to estimate a state of a channel based on a received signal; a storage configured to store a codebook including channel state values; an index of search number acquisition unit configured to acquire index of search number of candidates to be selected from among the channel state values for a correlation calculation with the estimated state value; a candidate selecting unit configured to select candidates for which the correlation calculation should be performed from among the channel state values according to the index of search number; a correlation calculation unit configured to calculate a correlation between the estimated state value and each of selected candidates; a selection unit configured to select a candidate having a highest correlation value; and a reporting unit configured to report a selected candidate to the base station.

Abstract: Before data is transmitted from a plurality of antennas, a plurality of known symbol sequences are transmitted from these antennas. Each known symbol sequence contains a plurality of known symbols having different subcarrier arrangements. Known symbols transmitted from different antennas have different subcarrier arrangements.

Abstract: A wireless transmission device which communicates with a wireless reception device is provided with a transmission-signal-generating unit configured to generate, transmission signals having transmission rates arranged in order corresponding to an input order of data items of the information sequence. The transmission device is also provided with a preamble adder which adds, to the transmission signals, respective preamble signals assigned in order of the transmission rates and used for estimation of channel responses at the wireless reception device. The transmission device is further provided with transmission units configured to transmit the transmission signals with the preamble signals added thereto.

Abstract: A wireless communication apparatus performs simultaneous communication with a plurality of communication terminals by using the same frequency band. The apparatus including: a reception unit that receives feedback information from each of the communication terminals; an acquisition unit that acquires a correlation value between the latest feedback information and the feedback information previously stored in a storage unit for each of the communication terminals; a measurement unit that measures a delay time relating to the feedback information; a generation unit that generates a reliability parameter representing degree of error that is allowed in the feedback information based on the correlation value and the delay time; and a selection unit that selects two or more of the communication terminals from among the plurality of the communication terminals based on the reliability parameter.